<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <ul id="lstBooks">
        <li>Java</li>
        <li>Python</li>
    </ul>
    <input type="text" />
    <button id="btnAdd">Add</button>
    <button id="btnDel">Del</button>
    <script>
        const oBooks 

    </script>
</body>
</html>